Automotive vehicles incorporate a variety of restraint systems to provide for the safety of vehicle occupants. For example, it is known in the vehicle art to provide various types of seat belts or restraint systems for restraining an occupant in his or her seat and providing controlled deceleration of portions of the body to limit the forces applied to the occupant's body during rapid deceleration of a vehicle from a cause such as a collision. Various types of seat belts and restraint systems have been used in automobiles, trucks, and other vehicles and are commonly known today.
Known seat belt systems typically used in commercially available production vehicles are three-point restraint systems with a lap belt and a shoulder belt extending over one shoulder of the occupant and connecting with the lap belt. The lap belts are anchored at one end, to the seat or to the vehicle adjacent the seat. The shoulder belts are connected at one end to the vehicle or to the seat and at the other end to the lap belt or lap belt buckle mechanism.
Four, five, and six-point restraint systems are among some of the seat belt and restraint systems that are particularly utilized in off-road type vehicles and other sport-type vehicles in order to provide additional restraint for occupants over two and three-point restraint systems. These seat belt systems tend to have multiple adjustable cinching mechanisms and are awkward and difficult to operate and properly position on an occupant. They also may be less comfortable and more complex due to the multiple mechanisms and therefore not amenable to quick donning and doffing on multiple occasions as may be required in a passenger vehicle.
Of particular interest to the automotive industry today is the four-point seat belt restraint system. Some of the four-point seat belt systems currently envisioned are essentially parallel shoulder belts. While providing a certain degree of protection, the systems currently envisioned may cause the seat occupant discomfort as a consequence of the shoulder belts contacting the neck during belt use. In addition, this discomfort may well be exacerbated if the lateral spacing of the shoulder belt is small. For example, if the lateral spacing of the shoulder belt is 130 mm along an occupant's clavicles, discomfort may result, since the belts may contact the occupant's neck area. As a consequence use of the four-point seat belts might be less than that of three-point belts negating the expected improvement in performance in society as a whole.
A further difficulty created by four-point seat belt restraint systems that use parallel shoulder belts is that the belts will fit differently on different sized occupants. For example, the belts may be too wide for smaller occupants and may be too narrow for larger occupants depending on the centerline-to-centerline spacing. This could affect the ability to maintain the position of the seat belts on the shoulders of the occupants during normal vehicle operation as well as during an impact event.
Other difficulties with known four-point seat belt restraint systems relate to the buckling systems. Specifically, the buckle-tongue arrangement of some four-point seat belt systems, in which the left hand shoulder belt and lap belt are connected to the buckle (or to the tongue) and the right hand shoulder belt and lap belt are connected to the tongue (or to the buckle), may have the tendency to “ride up” or move in an upward direction, that is, away from the occupant's lap during normal vehicle operation. The effect of this “ride up” could result in pre-submarining of the occupant, thus possibly leading to submarining of the occupant in an impact event.
Accordingly, a need exists today for an improved four-point seat belt system for use in vehicles that provides proper and constant belt alignment during normal vehicle operation as well as during an impact event. Such a system must be comfortable to the wearer. In addition, a need also exists for a four-point seat belt restraint system that prevents pre-submarining by restricting the movement of the lap-belt portion of the belt system from the pelvis to the abdomen during an impact event.